Alachlor Research Articles

Degradation of micropollutants in secondary wastewater effluent using nonthermal plasma-based AOPs: The roles of free radicals and molecular oxidants

Emerging micropollutants (µPs) appearing in water bodies endanger aquatic animals, plants, microorganisms and humans. The nonthermal plasma-based advanced oxidation process is a promising technology for eliminating µPs in wastewater but still needs further development in view of full-scale industrial application. A novel cascade reactor design which consists of an ozonation chamber preceding a dielectric barrier discharge (DBD) plasma reactor with a falling water film on an activated carbon textile (Zorflex®) was used to remove a selection of µPs from secondary municipal wastewater effluent. Compare to previous plasma reactor, molecular oxidants degraded micropollutants again in an ozonation chamber in this study, and the utilization of different reactive oxygen species (ROS) was improved. A gas flow rate of 0.4 standard liter per minute (SLM), a water flow rate of 100 mL min−1, and a discharge power of 25 W are identified as the optimal plasma reactor parameters, and the µP degradation efficiency and electrical energy per order value (EE/O) are 84–98% and 2.4–5.3 kW/m³, respectively. The presence of ROS during plasma treatment was determined in view of the µPs removal mechanisms. The degradation of diuron (DIU), bisphenol A (BPA) and 2-n-octyl-4-isothiazolin-3-one (OIT) was mainly performed in ozonation chamber, while the degradation of atrazine (ATZ), alachlor (ALA) and primidone (PRD) occurred in entire cascade system. The ROS not only degrade the µPs, but also remove nitrite (90.5%), nitrate (69.6%), ammonium (39.6%) and bulk organics (11.4%). This study provides insights and optimal settings for an energy-efficient removal of µPs from secondary effluent using both free radicals and molecular oxidants generated by the plasma in view of full-scale application.

(Invited) Advanced Oxidation Process of Micropollutants Removal from Wastewater through Plasma Based Technology

During the last century, global population growth, combined with raising living standards resulted in the large-scale production of new compounds such as pharmaceuticals, pesticides, plasticizers and many other chemicals. Many of them are more and more often present in drinking and technological water all over the world. Since 1970, these relative new class of organic contaminants, also referred to as “micropollutants”, have been systematically detected at very low concentrations (µg/l – ng/l). Among them, pesticides have endocrine disruptive, carcinogenic or bioaccumulative properties and are therefore considered hazardous even in trace concentrations of sub-ppm level. Since municipal wastewater treatment plants (MWWTPs) are generally recognized as the major access point of micropollutants into the aquatic environment, the ongoing detection of trace organics demonstrated its incapability in completely eliminating micropollutants. On industrial level, removal of micropollutants is a challenging task due to their high chemical stability, low concentration, and very long lifetime. At Ghent University, the Research Unit Plasma Technology (RUPT), has developed its expertise in novel plasma assisted water treatment for more than 10 years. RUPT successfully applied advanced water treatment by a combination of a pulsed powered direct barrier discharge over a moving water film with absorption on active carbon material [1,2].RUPT studied plasma assisted water treatment of several pesticides: atrazine (ATR), alachlor (ALA), dichlorvos (DVOS), diuron (DIU), pentachlorophenol (PCF), and isoproturon, since they are good representatives of persistent and hazardous micropollution in water. A novel approach combining activated carbon adsorption, non-thermal plasma treatment and ozonation was proposed for the removal of persistent pollutants from water. The study aims an examination of micropollutants removal in view of optimal micropollutant elimination. Prior to optimization of the plasma reactor system, the generation of different active species (O3, H2O2, NO3 - and NO2 -) has been studied [3]. It is shown that presence of N2 in the plasma forming gas is unfavorable and leads to very low efficiency of the treatment due to formation of NOx being OH scavenger. The kinetics of micropollutants decomposition by non-thermal electrical discharge was determined through GC-MS and HPLC methods as a function of input power, duty cycle and type of the used gas. Oxidation by-products for all studied pesticides were examined. Pathways of pesticides destruction were compared with ozonation process showing deeper plasma oxidation with lower selectivity of oxidation that is beneficial for industrial applications. In order to study possible industrial scale up of the process of the plasma treatment the efficiency of conventional UV, O3 and H2O2 based water treatment with a relatively new plasma based process, in terms of removal and energy efficiency was investigated. The experimental study on a synthetic water matrix spiked with four different micropollutants: atrazine (ATZ), alachlor (ALA), bisphenol A (BPA) and 1,7-α-ethinylestradiol (EE2) was performed [4]. For the different processes examined in this study, ozonation was more effective compared to UV based techniques in terms of energy efficiency. Although the energy efficiency of plasma-ozonation falls between the energy cost of O3 and UV-based AOPs, the removal kinetics generally proceed faster compared to other AOPs, achieving complete elimination (> 99.8 % removal) of the target compounds within short treatment time. Moreover, the results suggest that improvement in the mass-transfer in the plasma-ozonation setup permits to further decrease the energy cost of this process up to electrical energy per order (EE/O) values already close to the accepted value in industrial applications.

Oxidative Treatments of Pesticides in Rainwater Runoff by HOCl, O3, and O3/H2O2: Effects of pH, Humic Acids and Inorganic Matters

This study systematically investigated the oxidative treatment of five selected pesticides, alachlor (ALA), carbendazim (CAR), diuron (DIU), pyrimethanil (PYR), and tebuconazole (TEB), by comparing their relative reactivities as a function of three different oxidative treatment processes (i.e., chlorine (HOCl), ozone (O3), and ozone/hydrogen peroxide (O3/H2O2)) under various oxidant dosages, reaction times, and pH conditions. For oxidative treatment, pesticide standards were spiked into rainwater. The removal efficiency of the selected pesticides varied considerably depending on the oxidative treatment processes. HOCl, O3, and O3/H2O2 treatments were highly effective at eliminating CAR (>80%) and PYR (>99%), while they were not significantly effective in removing TEB (<20%). In the case of DIU, HOCl (81%) was shown to be more effective than O3 (24%) and O3/H2O2 (49%). The removal efficiency of ALA was in the order of O3/H2O2 (49%) > O3 (20%) > HOCl (8.5%). The effect of increasing the solution pH from 5.0 to 9.0 on pesticide degradation varied between the oxidative treatment processes. Additionally, NH4+, NO2−, and humic acid in rainwater significantly inhibited pesticide degradation.

Micropollutant elimination by O3, UV and plasma-based AOPs: An evaluation of treatment and energy costs

Over the last years, there has been a growing interest in the use of Advanced Oxidation Processes (AOPs) for the elimination of micropollutants. This work attempts to compare the efficiency of conventional UV, O3 and H2O2 based AOPs with a relatively new AOP based on plasma-ozonation, in terms of removal and energy efficiency. The experimental study is performed in a synthetic water matrix spiked with four different micropollutants: atrazine (ATZ), alachlor (ALA), bisphenol A (BPA) and 1,7-α-ethinylestradiol (EE2). For the different processes examined in this study, O3 – based AOPs are more effective compared to UV based techniques in terms of energy efficiency. Although the energy efficiency of plasma-ozonation falls between the energy cost of O3 and UV-based AOPs, the removal kinetics generally proceed faster compared to other AOPs, achieving complete elimination (>99.8% removal) of the target compounds within 20 min of treatment. Moreover, the results suggest that improvement in the mass-transfer in the plasma-ozonation setup permits to further decrease the energy cost of this process up to electrical energy per order (EE/O) values between 2.54 and 0.124 kWh m−³, which is already closer to the energy efficiency of ozonation (EE/O = 0.73–0.084 kWh m−³).

Combining ozone with UV and H2O2 for the degradation of micropollutants from different origins: lab-scale analysis and optimization

ABSTRACT The degradation of micropollutants (MPs), including pesticides, herbicides, pharmaceuticals and endocrine disrupting compounds, by ozone-based advanced oxidation techniques (AOP) was investigated in this study. The effect of different factors, such as ozone concentration, hydrogen peroxide concentration and initial pH, on the removal rate was studied in detail. The combination of UV with ozone/ H2O2 increased the MPs degradation. For example, atrazine removal increased from 12.6% to 66.9%. Increasing the concentration of ozone and H2O2 can enhance the degradation efficiency of MPs, while excess H2O2 plays a role as a scavenger for •OH. In addition, the optimizing conditions of degradation of MPs by an ozone-based AOP were investigated in this study. The optimal dosages of ozone for atrazine (ATZ), alachlor (ALA), carbamazepine (CBZ), 17-α-ethinylestradiol (EE2) and pentachlorophenol (PCP), were in the range of 0.6–0.75, while for ATZ a much higher dosage (5.4 mg/l) is needed. The optimal dosages of H2O2 concentration were at 0.75, 0.2, 0.47, 0.75 and 0.63 mM, and pH were at 10, 10, 7, 10 and 10, and reaction time at 38.5, 33.5 43, 6 and 6 min, respectively. Ozone-based AOP and in particular combination of UV with ozone and H2O2 is efficient to degrade atrazine, alachlor, carbamazepine, 17-α-ethinylestradiol and pentachlorophenol, and is attractive for future application of real wastewater treatment.

Bench- and pilot-scale studies on the removal of pesticides from water by VUV/UV process

As an advanced oxidation process, vacuum ultraviolet/ultraviolet (VUV/UV) process has recently gained increasing attention in water treatment, but assessment of its technical and economic feasibility for pesticide removal has rarely been conducted. This study investigated the degradation of five typical pesticides, including aldicarb (ALD), alachlor (ALA), chloroneb (CHL), methiocarb (MET) and atrazine (ATR), by VUV/UV under simulated water treatment conditions at both bench- and pilot-scales. Bench-scale tests showed that pesticide degradation followed pseudo-first-order kinetics and all pesticides were degraded by >90% at a VUV fluence of 12 mJ cm−2. The second-order reaction rate constants of ALD, ALA, CHL, MET and ATR with HO were 7.57 × 109, 4.89 × 109, 2.57 × 109, 3.81 × 109 and 2.38 × 109 M−1 s−1, respectively. Solution pH had varying influences on the degradation of different pesticides by VUV/UV. Inorganic anions (Cl−, NO3−, HCO3−) and natural organic matter (NOM) inhibited pesticide degradation by scavenging HO, but SO42− slightly promoted pesticide degradation. The toxicity of pesticide solutions was reduced by 33.7% to 74.8% after the VUV/UV treatment. In a long-term (80 d) operation of the pilot reaction system using a sand-filtered water, the stable performance with acceptable energy consumption (0.27–1.52 kWh m−3 Order−1) suggested a good application potential of the VUV/UV process for pesticide removal in small-scale water treatment.

Electrochemical impedance sensor for herbicide alachlor based on imprinted polymer receptor

Alachlor (ALA), a carcinogenic herbicide is detected in surface and groundwater, as well as in milk, eggs, and meat. So, the sensitive detection of ALA is essential for humans. To respond, we report a molecularly imprinted polymer (MIP) receptor for simple electrochemical sensing of ALA. The MIP film was immobilized onto glassy carbon electrode by electrodeposition of o‑phenylenediamine (o‑PD) in the presence of ALA as a template, followed by the ALA leaching out to create specific recognition cavities to ALA. The stepwise fabrication of the sensor was characterized by recording cyclic, square wave voltammetry peak currents and the electron transfer resistance (Ret) where the [Fe(CN)6]3−/4− was used as an electro-active probe. The mole ratio of ALA to o‑PD as well as the controlled release of the alachlor from the MIP‑o‑PD network was optimized to create a maximum number of free imprinted sites that affected the sensor sensitivity and its linear range. The increment in the Ret of the redox probe [Fe(CN)6]3−/4− upon selective recognition of ALA to the free cavities of MIP film is employed as the sensor response. At the optimal experimental conditions, the relative change in Ret is linearly correlated to the ALA concentrations in a range of 1 nM to 1 μM ALA. This sensor shows the high sensitivity of ALA with a limit of detection of 0.78 nM ALA. The affinity of MIP to ALA is proved by calculating the dissociation constant (Kd) in nM range. The high selectivity of the MIP sensor against the interferences propachlor and metalaxyl has been confirmed. Finally, the reliability of MIP-GCE for ALA detection is proved in tap water samples spiked by ALA. These findings indicate that such a sensor can be used for in-field measurements of other herbicides as a simple detection platform.

Occurrence, distribution, and fate of pesticides in an intensive farming region in the Brazilian semi-arid tropics (Jaguaribe River, Ceará)

This study is the first to assess herbicide levels in sediment of the Jaguaribe River, which is located in one of the largest agricultural areas of the tropical Brazilian semi-arid region (Ceara state), with the goal of evaluating the occurrence of herbicides as well as their geographical distribution pattern and environmental fate in this river. Sediment collection was performed in October 2012, and nine points were selected located along the river to its mouth, and the levels of atrazine (ATR), alachlor (ALA), bromacil (BRO), ethalfluralin (ETHA), fluridone (FLU), metolachlor (METO), norflurazon (NOR), simazine (SIM), tebuthiuron (TEB), and trifluralin (TRI) were determined. Sediment from each site was characterized by granulometric analysis and total organic carbon (TOC), humic acid (HA), and fulvic acid (FA) contents. ALA, BRO, ETHA, FLU, NOR (a prohibited compound), and TEB were detected in all samples analyzed, whereas herbicides ATR, METO, SIM, and TRI were not detected at any of the sampling sites. The total herbicide concentrations (∑herb) (the sum of six herbicides detected) per sampling sites ranged from 174.86 to 348.84 ng g−1 (fluvial zone) and 111.43 to 419.35 ng g−1 (estuary zone). The results showed that the sum of ETHA concentrations at all sampling points (ΣETHA) (1687.47 ng g−1) was the most abundant herbicide, followed by ΣBRO (201.43 ng g−1), ΣALA (41.73 ng g−1), ΣTEB (24.41 ng g−1), ΣFLU (1.33 ng g−1), and ΣNOR (0.43 ng g−1). The physicochemical properties of ATR, METO, and SIM favor their dispersion in the aqueous fraction; thus, the lack of these herbicides in the sediments is due to environmental partitioning. The environmental and geographical distribution pattern indicates that the estuarine zone is a sink that controls the fate of TEB, ALA, and FLU herbicides. Differently from expected results, data based on non-linear Spearman’s coefficient show that herbicides with high log K ow and K oc values were more likely to be found in the sediment inorganic fraction, whereas herbicides with high solubility and low K oc values were dispersed between both the organic and inorganic fractions of sediments.

The Saccharomyces cerevisiae response to stress caused by the herbicidal active substance alachlor requires the iron regulon transcription factor Aft1p.

In the Saccharomyces cerevisiae eukaryotic model, the induction of the iron regulon genes ARN1, FIT2 and CTH2 by growth-inhibitory concentrations of alachlor (ALA) was dependent on Aft1p expression. This transcription factor was found to be activated through its nuclear localization. The hypersensitivity of the aft1Δ mutant to ALA was abrogated by surplus exogenous iron, suggesting that the role of Aft1p in ALA tolerance may be associated with iron limitation under ALA stress. A transient decrease in the cellular iron content in the ALA-stressed cells supported this idea. In contrast to the upregulation of the nonreductive iron uptake genes ARN1 and FIT2 by ALA, thequantity of FET3 and FTR1 transcripts encoding the high-affinity iron uptake reductive pathway decreased. Yeast cells were apparently more sensitive to ALA when iron uptake occurred through the reductive pathway than when the nonreductive uptake of ferrichrome-bound ferric iron was dominant. On the other hand, the ALA hypersensitivity of the aft1Δ mutant was reversed by medium supplementation with glutathione or N-acetyl-L-cysteine. The results are compatible with possible links between ALA toxicity and perturbations in metal and antioxidant homeostasis, which may be relevant for environmental microbes and higher eukaryotes in situations of inadvertent herbicide contamination.

Tolerância de duas variedades de algodoeiro a herbicidas aplicados em pré-emergência

Este trabalho teve por objetivo avaliar a seletividade de herbicidas aplicados em pré-emergência, isolados ou em misturas, para as variedades Delta-Opal e FMT-701. Os tratamentos avaliados foram: alachlor, S-metolachlor, diuron (em duas doses), prometryn (em duas doses), oxyfluorfen, alachlor + diuron, alachlor + prometryn (em duas doses da mistura), S-metolachlor + diuron, S-metolachlor + prometryn (em duas doses da mistura), oxyfluorfen + diuron, oxyfluorfen + prometryn. Foram realizadas avaliações relacionadas à fitointoxicação visual, altura de plantas e produtividade da cultura. Quando houve incremento na dose de diuron e prometryn, os sintomas de fitointoxicação foram intensificados em relação às menores doses. O herbicida oxyfluorfen quando aplicado isolado e em mistura com diuron ou prometryn proporcionou sintomas intensos de fitointoxicação à cultura do algodoeiro. No entanto, o único tratamento que não foi seletivo para ambas variedades de algodoeiro foi a mistura oxyfluorfen + prometryn (0,192 + 0,900 kg ha-1).

Determination of alachlor in serum by gas chromatography

目的 建立甲草胺中毒患者血清中甲草胺的气相色谱检测法.方法 取静脉血3.0 ml,待凝固后高速离心,取1.0 ml血清于带塞玻璃试管中,加2.0 ml乙酸乙酯充分振荡萃取,取乙酸乙酯层于锥形试管中,氮气吹干,残渣用50.0μl乙醇定容,取1.0μl进样,以保留时间定性,峰面积外标法定量.结果 甲草胺线性范围为0.5～20.0 μg/ml,平均回收率88.9％～103.8％;日内和日间相对标准差(RSD)分别为2.50％～4.26％和3.26％～4.51％,最低检出浓度0.1 μg/ml.回归方程y=1890.6x+205.8,r=0.9993.结论 SE-54毛细管柱分离,气相色谱法检测血清中甲草胺,方法简便快速,灵敏度高,分离杂峰少且容易判定,可以满足临床检测需要。

The usefulness of mesocosms for ecotoxicity testing with lacertid lizards

Mesocosms (i.e., outdoor, man-made representations of natural ecosystems) have seldom been used to study the impact of contaminants on terrestrial ecosystems. However, mesocosms can be a useful tool to provide a link between field and labo- ratory studies. We exposed juvenile lacertid lizards for a period of over one year to pesticides (herbicides and insecticides) in mesocosm enclosures with the intention of validating field observations obtained in a previous study that examined the effects of corn pesticides in Podarcis bocagei . Our treatments replicated field conditions and consisted of a control, an herbicides only treatment (alachlor, terbuthylazine, meso- trione and glyphosate) and an herbicides and insecticide treatment (including chlor - pyrifos). We used a multi-biomarker approach that examined parameters at an indi- vidual and sub-individual level, including growth, locomotor performance, standard metabolic rate, biomarkers of oxidative stress, esterases and liver histopathologies. Although mortality over the course of the exposures was high (over 60%), surviving individuals prospered relatively well in the mesocosms and displayed a broad range of natural behaviours. The low numbers of replicate animals compromised many of the statistical comparisons, but in general, surviving lizards exposed to pesticides in mesocosm enclosures for over one year, thrived, and displayed few effects of pesticide exposure. Despite the difficulties, this work acts as an important stepping-stone for future ecotoxicology studies using lizards.

Glyphosate, Alachor and Maleic Hydrazide have Genotoxic Effect on Trigonella foenum-graecum L.

In the present study effects of herbicides glyphosate (GP), alachlor (AL) and maleic hydrazide (MH) is studied on mitotic cells of Trigonella foenum-graecum L. Seeds of T. foenum-graecum L. treated with a series of concentrations ranging from 0.1%, 0.2%, 0.3%, 0.4% and 0.5% for 1, 2 and 6 h and their effect on mitotic index and chromosomal aberrations was studied. The results indicate that these herbicides reduced mitotic index in dose-dependent manner. In addition, increase in the percentage of abnormal mitotic plates was observed in herbicide treated groups which was both concentration and time dependent. Commonly observed abnormalities were c-mitosis, laggards, bridges, stickiness, c-anaphase, precocious separation, un-equal distribution and fragments. The result of the present investigation indicates that commonly used herbicides GP, AL and MH have significant genotoxic effect on T. foenum-graecum plant.

Simultaneous determination of pre-emergence herbicides in environmental samples using HPLC-DAD combined with second-order calibration based on self-weighted alternating trilinear decomposition algorithm

This work presents a novel strategy for simultaneous and rapid quantitative analysis of three pre-emergence herbicides in environmental samples using HPLC-DAD combined with second-order calibration based on the self-weighted alternating trilinear decomposition (SWATLD) algorithm. The sample preparation procedure was simplified only by using water as solvent and methanol as extractant and data were measured in less than 4.2 min by applying an isocratic mode. Although the elution and spectral profiles of the analytes, prometryne (PRO), napropamide (NAP) and alachlor (ALA), are heavily overlapped with each other and with matrix constitutes, the method not only extracts the profiles of the analytes, but also simultaneously determines the concentrations of them in actual complex systems, i.e., river sediment and wastewater samples. In the analysis of river sediment and wastewater samples, the obtained average recoveries were 99 ± 6% and 98 ± 5% for PRO, 108 ± 6% and 100 ± 4% for NAP and 98 ± 5% and 97 ± 4% for ALA, respectively. Furthermore, the accuracy and precision of the proposed method was also evaluated through elliptical joint confidence region tests as well as figures of merit. Such a chemometrics-based protocol may be a very promising tool for more analytical applications in environment monitoring, due to its advantages of easy sample pretreatment, green, sufficient spectral resolution and concentration prediction even in the presence of unknown interferences.

Analysis of Some Selected Persistent Organic Chlorinated Pesticides in Marine Water and Food Stuffs by Differential Pulse‐Cathodic Stripping Voltammetry

AbstractBased on the redox characteristics of two selected organochlorine pesticides namely alachlor (ALC) and chlorfenvinphos (CHL) in Britton–Robinson (B–R) buffer at a hanging mercury drop, Pt and Au working electrode (HMDE), a fast, simple and selective differential pulse cathodic stripping voltammetric (DP CSV) method was developed for their determination. The cathodic stripping peak currents for ALC versus concentrations was linear in the range from 7.4×10−9 to 1.4×10−7 mol L−1 and in the range from 2.7×10−9 to 1.6×10−8 mol L−1 for CHL. The method was applied for the analysis of trace concentrations of ALC and CHL in fresh‐ and marine water (Atlantic and Red Sea) and sediment samples and food stuffs.

Adsorption of cellular peptides of Microcystis aeruginosa and two herbicides onto activated carbon: Effect of surface charge and interactions

In this research, the adsorption of two herbicides, alachlor (ALA) and terbuthylazine (TBA), on granular activated carbon (GAC) in the presence of well-characterized peptide fraction of cellular organic matter (COM) produced by cyanobacterium Microcystis aeruginosa was studied. Two commercially available GACs were characterized using nitrogen gas adsorption and surface charge titrations. The COM peptides of molecular weight (MW) < 10 kDa were isolated and characterized using MW fractionation technique and high-performance size exclusion chromatography (HPSEC). The effect of surface charge on the adsorption of COM peptides was studied by means of equilibrium adsorption experiments at pH 5 and pH 8.5. Electrostatic interactions and hydrogen bonding proved to be important mechanisms of COM peptides adsorption. The adsorption of ALA and TBA on granular activated carbon preloaded with COM peptides was influenced by solution pH. The reduction in adsorption was significantly greater at pH 5 compared to pH 8.5, which corresponded to the increased adsorption of COM peptides at pH 5. The majority of the competition between COM peptides and both herbicides was attributed to low molecular weight COM peptides with MW of 700, 900, 1300 and 1700 Da.

Mating and Oviposition Behaviors and Rhythms of Delphastus catalinae (Horn)

Thirty nine agrochemicals comprising eighteen fungicides, eleven insecticides, six fertilizers and four herbicides were evaluated at different concentrations against two isolates of Trichoderma spp., and EC 50 and EC 90 values were calculated based on inhibition in radial growth. Isolate T. virens TV9, obtained from citrus orchard-relatively less exposed to agrochemicals was found more sensitive compared to isolate T. harzianum Th4, obtained from cotton ecosystem relatively more exposed to agrochemicals. Among fungicides, benzimidazoles showed higher toxicity followed by chlorothalonil and triazoles when mean EC 50 values were compared. Wettable sulphur, Bordeaux mixture, azoxystrobin and mancozeb were found to be less toxic to Trichoderma spp. Among insecticides, organophosphorous group was found more toxic while carbofuran followed by spinosad were least toxic. Among fertilizers Zinc sulphate and diammonium phosphate were found highly toxic whereas potassium nitrate, muriate of potash and ammonium sulphate showed less toxicity. All the four test herbicides, i.e., pendimethalin, alachlor, glyphosate and 2, 4-D were found to be toxic to Trichoderma spp.

Removal of organic pollutants from water by modified cellulose fibres

Different modified cellulose fibers were prepared and their efficiency as adsorbent for the removal of several aromatic organic compounds and three herbicides, i.e.; Alachlor (ACH), Linuron (LNR) and Atrazine (ATR), was investigated. The evolution of the adsorption capacity according to the solute structure and the modification sequence was explored. The modification was carried on under heterogeneous conditions using N,N′-carbonyldiimidazole (CDI) as an activator and different amino derivatives as grafting agent. By varying the structure of the amino derivative and the reaction sequence, different organic structures bearing diverse functional groups were generated on the surface. Evidence for the occurrence of the surface modification was confirmed by FTIR, XPS and solid-state 13C NMR spectroscopy. It was shown that the chemical modification of the fibers’ surface greatly enhanced the adsorption capacity toward organic compound dissolved in water. The adsorption capacity evolved from 20 to 50 μ mol g −1for the virgin fibers to between 400 and 1000 μ mol g −1 for the modified substrates, depending on the solute structure and the modification sequence. The efficiency of the retention property under a continuous regime was also confirmed by using a column filled with the modified fibres. Once exhausted, the column could be reused by washing its contents with ethanol, which totally extracted the trapped compounds. The regenerated column was then used in several adsorption–desorption cycles without any loss of the capacity.

Compatibility of mutant isolates of Trichoderma spp. with agrochemicals.

Two stable mutants, one each of Trichoderma viride (TvM 1 ) and Trichoderma harzianum (ThM 1 ), obtained through gamma radiation were tested for their compatibility with different pesticides in order to fit them in integrated disease management for the control of fusarial wilt of chilli. Both the fungal mutants showed high compatibility carbendazim (0.1%), fipronil (0.2%), imidacloprid (0.025%) and fluchloralin (0.33%). TvM 4 showed compatibility with captan (0.25%), copper oxy chloride (0.15%), phosalone (0.1%) and butachlor (0.2%) and ThM 1 , was compatible with mancozeb (0.125%) and phosalone (0.1%). Mancozeb (0.25%), copper oxy chloride (0.3%), dicofol (0.5%), pendimethalin (0.66%) and alachlor (0.4%) were found to be highly inhibitory to the radial growth of the mutants TvM 1 and ThM 1 .

Determinação de herbicidas usados no cultivo de arroz irrigado na região sul do estado de Santa Catarina através da SPME-GC-ECD

-1 for atrazine, alachlor and propanil, respectively. The herbicides were quantified by GC-ECD and identified by GC-MS. Both of the selected rivers presented contamination by at least one of the studied herbicides.